Definitions of gravity; a glass-tube quicksilver balance
Several restated definitions of weight, and a steelyard of glass filled with quicksilver marked in pounds and ounces
The page gathers a series of restated definitions of gravity, each casting it as a natural power or 'desire of flight' arising when a part of one element is violently drawn out of it and carried into another, so that it presses on whatever opposes its return home. A body's surface is said to enclose innumerable centres of only three kinds. At the lower right Leonardo sketches and describes a weighing instrument: a steelyard or balance whose glass tube holds a little vessel of quicksilver and is graduated in pounds, ounces, pennyweights and grains.
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Gravity as a 'desire of flight' of displaced elements
Gravity is defined and redefined as a natural power born of the violent motion of the parts of one element when they are drawn out of it and carried into another; it is the parts' desire to return home, a thrusting or flight that presses continually on whatever opposes their return. It arises whenever a part of an element is set where neither it can stay nor the other will receive it.
A steelyard of glass filled with quicksilver
A kind of steelyard or balance for weighing is drawn and described: its tube is of glass and the little vessel is full of quicksilver, and on the tube are marked the pounds, ounces, pennyweights and grains as one needs. It will be accurate and good if well made.